The present disclosure relates to compositions and methods for use in subterranean operations.
The unwanted production of water from hydrocarbon-producing wells constitutes a considerable technical problem and expense in oilfield operations. When a subterranean formation contains water in significant amounts, water's higher mobility often allows it to flow to a well bore penetrating the formation by way of natural and manmade fractures and high permeability zones. If the ratio of recovered water to recovered hydrocarbons becomes sufficiently large, the cost of separating the water from the hydrocarbons and disposing of it can become a barrier to continued production. This can lead to abandonment of a well penetrating a subterranean formation, even when significant amounts of hydrocarbons remain therein.
In order to reduce the undesired production of water from hydrocarbon-producing subterranean formations, aqueous-soluble polymer systems containing crosslinking agents have been utilized in the art to enter water-containing zones of the formation and block the flow of water therefrom. Selective placement of these crosslinked polymers in a subterranean formation and stability therein represent significant technical challenges that have somewhat limited their use. A more recent strategy to reduce water production from a subterranean formation has been to utilize agents known as relative permeability modifiers. As used herein, the term “relative permeability modifier” refers to a polymer that selectively reduces the effective permeability of a subterranean formation to water-based fluids. Such relative permeability modifiers are capable of significantly reducing the flow of water from a subterranean formation while having a minimal effect on the flow of hydrocarbons. The use of relative permeability modifiers does not generally necessitate the use of zonal isolation techniques that are often employed with crosslinked polymers.
While embodiments of this disclosure have been depicted, such embodiments do not imply a limitation on the disclosure, and no such limitation should be inferred. The subject matter disclosed is capable of considerable modification, alteration, and equivalents in form and function, as will occur to those skilled in the pertinent art and having the benefit of this disclosure. The depicted and described embodiments of this disclosure are examples only, and not exhaustive of the scope of the disclosure.